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Post by robbiegong on Apr 11, 2015 20:27:52 GMT
Do any of you guys skew your cartridge in the headshell to any degree to follow arc and sit perfectly squarely in the null point grid ? This is in respect of the Rega Baerwald Arc Protractor. It really isn't easy to follow arc and sit squarely in the grid. I have room for movement in the ADC magnesium headshell I use. Some tips, advise and experience / opinions would be much appreciated.
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Post by Mr Whippy on Apr 11, 2015 22:03:43 GMT
Try setting up a cartridge in a Stanton STR 8 150. I just couldn't get it parallel with the lines on the two reference points of the Hi Fi World gauge I used.
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Post by MartinT on Apr 11, 2015 23:26:01 GMT
I set mine up with the headshell mounting guide provided by Dynavector and ensure the cartridge body is parallel with the headshell. I'm not sure which alignment this uses, but I never have any problem with tracking or end of side distortion.
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Post by Deleted on Apr 12, 2015 8:00:50 GMT
For anyone who wants to get analytical about cartridge set up, there are some highly technical papers that set out where then null points are here www.helices.org/auDio/turnTable/And interestingly (but no surprisingly) it depends on what size records you principally play. Because the inner and outer groove radii are different for 7", 10", 12" and 78's, the null points are in at different radial positions. Baerwald's 1941 paper is in the link, and is a seriously mathematical read (as are all four papers there) |
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Post by Mr Whippy on Apr 12, 2015 9:54:41 GMT
Well for whatever reason, the Stanton deck is the only one I've ever had a problem with with regards setting up a cartridge.
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Post by Deleted on Apr 12, 2015 10:35:33 GMT
And the reason for that is that the STR 8 150 has a straight tone arm. All alignment gauges that I know of only work with an offset arm. So you will never be able to set the STR 8 150 with a hi-fi world, or any other setting gauge. The Baerwald paper covers how to set up a straight arm. But straight arms always produce much more distortion that offset ones - but since the STR 8 150 is a disco deck that is a secondary consideration www.stantondj.com/stanton-turntables/str8-150.htmlGiven the inherently very high distortion of a straight arm, I really wouldn't bother with detailed setting up though. Rule of thumb is 31/L percent when in "perfect" alignment, where L is arm length in inches. So a 9" straight arm will produce 3.4% harmonic distortion. |
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Post by Mr Whippy on Apr 12, 2015 11:34:12 GMT
Well, yes, I'm aware of that, but even taking that into account and off-setting the cartridge to compensate for no off-set, it still wouldn't track the two reference points. Others have found the same.
Yes the Stanton is a disco deck - just like a 1210, albeit with it's s-shaped arm.
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Post by MartinT on Apr 12, 2015 11:43:42 GMT
A straight tonearm is a sacrifice to fashion, there is no good reason to use such a device, which creates far more tracking distortion than is necessary. I can't see the point, it is engineering-ugly.
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Post by ChrisB on Apr 12, 2015 11:51:22 GMT
It's no sacrifice to fashion in the Viv Lab tonearm.  I can't vouch for it's efficacy but it does have a good reputation. Short TAS thread with links here. |
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Post by MartinT on Apr 12, 2015 12:03:14 GMT
Surely that offsets the cartridge, Chris? That's not what we're discussing here.
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Post by ChrisB on Apr 12, 2015 12:09:09 GMT
Apparently not.  |
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Post by Deleted on Apr 12, 2015 12:33:31 GMT
The rationale to that £5k arm is primarily to overcome side force - usually overcome with an antiskating device in an offset arm. Whether that is worth the severalfold increase in distortion is a moot point.
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Post by Deleted on Apr 12, 2015 12:44:23 GMT
Well, yes, I'm aware of that, but even taking that into account and off-setting the cartridge to compensate for no off-set, it still wouldn't track the two reference points. Others have found the same. Yes the Stanton is a disco deck - just like a 1210, albeit with it's s-shaped arm. It won't and can't for a straight arm. The null points on an alignment protractor only work with an offset arm. The tracking error for a straight arm is monotonic - so there is only one single radius for which tracking error is zero. An offset arm has two zeros, hence the two alignment points on a protractor. If you are skewing the cartridge in an attempt to generate an offset, you have to have the correct offset angle to rather a high degree of accuracy for the nulls to work right. Lots of trial and error. |
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Post by MartinT on Apr 12, 2015 13:38:04 GMT
I'm very surprised and cannot see how that can be a hi-fi solution with the error angles created at the start and end of sides. |
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Post by Deleted on Apr 12, 2015 14:11:19 GMT
Well, yes, I'm aware of that, but even taking that into account and off-setting the cartridge to compensate for no off-set, it still wouldn't track the two reference points. Others have found the same. Yes the Stanton is a disco deck - just like a 1210, albeit with it's s-shaped arm. Forgot to mention, if you are skewing the cartridge you need to get two things correct for it to work with an alignment protractor - offset angle AND pivot to stylus distance. The only way to do it the way you are trying to is a long iterative process. |
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Post by Deleted on Apr 12, 2015 14:39:37 GMT
Aha - you cannot align a Stanton STR8.150 even by offsetting the cartridge. The pivot/stylus length is 7.6" and alignment gauges are for use with 9" arms
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Post by ChrisB on Apr 12, 2015 15:15:33 GMT
I'm very surprised and cannot see how that can be a hi-fi solution with the error angles created at the start and end of sides. The rationale is outlined in this review Martin. |
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Post by MartinT on Apr 12, 2015 15:38:10 GMT
Thanks. Sacrificing up to 10° tracking angle error in favour of very low side-forces. An interesting proposal, and one that would pretty much disallow line contact stylii. I would have to hear it to be convinced, but I would like to.
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Post by Greg on Apr 12, 2015 21:11:12 GMT
I wouldn't use a Rega protractor. Basically it is wrong, even for a Rega arm, but it gets you roughly into the ball park. I've spent hours on this issue. Conclusion is, establish what stylus overhang you need to set and do it. Thereafter, cartridge alignment becomes a small move doddle. On Rega arms, have a look at the audiomods website. It'll simplify things and inspire you.
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Post by Mr Whippy on Apr 13, 2015 19:24:39 GMT
Aha - you cannot align a Stanton STR8.150 even by offsetting the cartridge. The pivot/stylus length is 7.6" and alignment gauges are for use with 9" arms I suppose that would explain it! I did try lots, and lots (and lots) of trial and error, but gave up. I did think it was probably down to the length of the arm as I couldn't get the cartridge any further forward. The arm does look short. Can't escape the fact. |
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